Cross-platform .NET UI Framework

Use established .NET standards and productivity tools for your cross-platform desktop application. Keep up good engineering practices. Deliver your application quickly. Be native on the desktop, whether it is Windows, macOS, or Linux.

AlterNET UI running on Windows, macOS and Linux

Develop cross-platform GUI applications with the full power of .NET

Native look and feel on Windows, macOS and Linux

Native look and feel on Windows, macOS, and Linux

AlterNET UI provides a UI Framework and a set of standard controls such as Text Box, Label, CheckBox, Button, Image, TreeView, ListView, and many more. These controls use native API through the platform abstraction layer and look and feel precisely like native elements on all supported platforms and different screen resolutions.

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Creating AlterNET UI project in Visual Studio

Built on .NET Framework and integrated with Visual Studio

AlterNET UI is built on top of the .NET Framework and uses a XAML-like approach to define the user interface and layout, allowing .NET developers to immediately use their skills to create cross-platform or native macOS/Linux applications.

With the AlterNET UI Visual Studio extension, you can use your favorite development environment and start developing cross-platform desktop applications in no time.

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Hello World code example

UIXML

<Window xmlns="http://schemas.alternetsoft.com/ui/2021"
  xmlns:x="http://schemas.alternetsoft.com/ui/2021/uixml"
  x:Class="HelloWorld.MainWindow"
  Title="My First Application">
  <StackPanel>
    <Button Name="HelloButton" Text="Say Hello" Margin="20" Click="HelloButton_Click" />
  </StackPanel>
</Window>

Code

using Alternet.UI;

internal partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }
    
    private void HelloButton_Click(object? sender, EventArgs e)
    {
        MessageBox.Show("Hello, world!");
    }
}
Explore examples
 
Intellisense for UIXML editing in Visual Studio

Industry-proven framework design

The design of AlterNET UI is inspired by Windows Forms and Windows Presentation Foundation (WPF) frameworks from Microsoft. Most .NET developers who are experienced with these frameworks will be already familiar with the basic concepts of AlterNET UI programming. It allows them to use the existing experience of utilizing standard UI controls and layout containers through UIXML and go cross-platform with ease. AlterNET UI can be added to your .NET application by a single-dependency NuGet package with a low-footprint deployment size.

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Rendering different fonts using AlterNET UI Drawing Context

Platform-independent graphics device interface

AlterNET UI includes a layer that abstracts implementation on different platforms for graphical objects, such as fonts, brushes, and images; control rendering and responding to the events; and a layout engine, enabling custom control development.

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